rút gọn :
\(\left(cos0+1\right).tan0+cosh0+5!-119\)
! là giai thừa nhé!
Rút gọn biểu thức :
a) \(4a^2\cos^260^0+2ab.\cos^2180^0+\dfrac{4}{3}\cos^230^0\)
b) \(\left(a\sin90^0+b\tan45^0\right)\left(a\cos0^0+b\cos180^0\right)\)
a)
\(4a^2cos^260^o+2ab.cos^2180^o+\dfrac{4}{3}cos^230^o\)
\(=4a^2.\left(\dfrac{1}{2}\right)^2+2ab.\left(-1\right)^2+\dfrac{4}{3}.\left(\dfrac{\sqrt{3}}{2}\right)^2\)
\(=4a^2.\dfrac{1}{4}+2ab+\dfrac{4}{3}.\dfrac{3}{4}\)
\(=a^2+2ab+1\).
b)
\(\left(asin90^o+btan45^o\right)\left(acos0^o+bcos180^o\right)\)
\(=\left(a+b\right)\left(a-b\right)=a^2-b^2\).
Giúp!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Rút gọn biểu thức(Với cách lâu dài nhé)
\(\left|x-1\right|+\left|x+5\right|\) Nhớ nhé ko cần tìm x đâu.Ai đúng mk tick cho nha
Rút gọn phân số:
a) \(\dfrac{2929-101}{2.1149+404}\)
b) \(\dfrac{6.9-2.17}{63.3-119}\)
c) \(\dfrac{3.13-13.18}{15.40-80}\)
d) \(\dfrac{-1997-1996+1}{\left(-1995\right).\left(-1997\right)+1996}\)
e) \(\dfrac{2.3+4.6+14.21}{3.5+6.10+21.35}\)
g) \(\dfrac{\left(-5\right)^3.40.4^3}{135.\left(-3\right)^{14}.\left(-100\right)^0}\)
h) \(\dfrac{18.34+\left(-18\right).124}{-36.17+9.\left(52\right)}\)
j) \(\dfrac{9.11+32.9}{23.15+12.23}\)
k) \(\dfrac{12.13+24.26+36.39}{24.26+48.52+72.78}\)
b) \(\dfrac{6\cdot9-2\cdot17}{63\cdot3-119}\)
\(=\dfrac{2\left(3\cdot9-17\right)}{7\cdot\left(3\cdot9-17\right)}\)
\(=\dfrac{2}{7}\)
Rút gọn biểu thức
\(\dfrac{3\left(\sqrt{5}-1\right)}{\left(\sqrt{5}+1\right)\left(\sqrt{5}+1\right)}\)
Ta có: \(\dfrac{3\left(\sqrt{5}-1\right)}{\left(\sqrt{5}+1\right)\left(\sqrt{5}+1\right)}\)
\(=\dfrac{3\left(\sqrt{5}-1\right)}{6+2\sqrt{5}}\)
\(=\dfrac{3\left(\sqrt{5}-1\right)\left(6-2\sqrt{5}\right)}{\left(6-2\sqrt{5}\right)\left(6+2\sqrt{5}\right)}\)
\(=\dfrac{3\left(6\sqrt{5}-10-6+2\sqrt{5}\right)}{16}\)
\(=\dfrac{3\left(8\sqrt{5}-16\right)}{16}\)
\(=\dfrac{3\cdot\left(\sqrt{5}-2\right)}{2}\)
1. Rút gọn phân thức \(\dfrac{\left(x+y\right)^2}{x^2-y^2}=\) ta được kết quả là:
2. Rút gọn phân thức \(\dfrac{x^2-3x}{x^2-9}=\)
giúp mình với nhé mình đang cần gấp ạ
1. = \(\dfrac{x+y}{x-y}\)
2. = \(\dfrac{x}{x+3}\)
Rút gọn lũy thừa:
A = \(\frac{8^5\cdot\left(-5\right)^8+2^5\cdot10}{2^{16}\cdot5^7+20^8}^9\)
\(\frac{2^{15}.5^8+2^{14}.5^9}{2^{16}.5^7+2^{16}.5^8}=\frac{2^{14}.5^8\left(2+5\right)}{2^{16}.5^7\left(1+5\right)}=\frac{2^{14}.5^8.7}{2^{16}.5^7.6}=\frac{5.7}{4.6}=\frac{35}{24}\)
rút gọn biểu thức \(\left(5-3x\right)\left(5+3x\right)-\left(x+1\right)^3\)
\(\left(5-3x\right)\left(5+3x\right)-\left(x+1\right)^3\)
\(=25-9x^2-x^3-3x^2-3x-1\)
\(=-x^3-12x^2-3x+24\)
1. Rút gọn biểu thức
\(\sqrt{\dfrac{4}{3}}+\sqrt{12}-\dfrac{4}{3}\sqrt{\dfrac{3}{4}}\)
2. Đưa thừa số vào trong dấu căn :
a. \(\left(2-a\right)\sqrt{\dfrac{2a}{a-2}}\) với a lớn hơn 2
b. với 0 bé hơn x, x bé hơn 5. \(\left(x-5\right)\sqrt{\dfrac{x}{25-x^2}}\)
c. Với 0 bé hơn a, a bé hơn b \(\left(a-b\right)\)\(\sqrt{\dfrac{3a}{b^2-a^2}}\)
Rút gọn các biểu thức sau
\(c,\left(3x+1\right)^2-2\left(3x+1\right)\left(3x+5\right)+\left(3x+5\right)^2\)
\(\left(3x+1\right)^2-2\left(3x+1\right)\left(3x+5\right)+\left(3x+5\right)^2\)
\(=\left[\left(3x+1\right)-\left(3x+5\right)\right]^2\)
\(=\left(3x+1-3x-5\right)^2\)
\(=\left(-4\right)^2=16\)